Difference between CROSSTOOL and CROSSTOOL.tpl

[aardeb]

Hi

What is the difference between /usr/local/src/bazel/tools/cpp/CROSSTOOL and /usr/local/src/bazel/tools/cpp/CROSSTOOL.tpl files ?

Which one should I modify to change my tool chain i.e to cross compile a solution building in bazel to another platform ?

Thanks

[hlopko]

Hi @fieldtest,

you almost definitely want to edit cc_configure.bzl and CROSSTOOL.tpl. I'm not sure CROSSTOOL is used for anything outside of tests. I'll take a look next week.

[aardeb]

Hi

Thanks for your reply. To give some further background on my approach

1. I downloaded the latest bazel version and built it from source

2. Since I am interested in ARM Cross Compilation I installed arm-linux-gnueabuhf tools through apt-get for Ubuntu 16.04 LTS.

3. I then built a simple Hello World Program

https://github.com/fieldtest/bazel_example

4. trying to compile using Bazel

bazel build --spawn_strategy=standalone --verbose_failures :hw
INFO: Found 1 target...
Target //:hw up-to-date:
bazel-bin/hw
INFO: Elapsed time: 0.519s, Critical Path: 0.31s

on the other hand running

bazel build --spawn_strategy=standalone --verbose_failures --cpu=armeabi-v7a :hw
INFO: Found 1 target...
ERROR: /usr/local/src/examples_PORT/BUILD:1:1: C++ compilation of rule '//:hw' failed: false failed: error executing command
(cd /home/fieldtest85/.cache/bazel/_bazel_root/6633de190a698b4224df2363f1b52550/execroot/examples_PORT &&
exec env -
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
/bin/false -MD -MF bazel-out/stub_armeabi-v7a-fastbuild/bin/_objs/hw/hw.pic.d '-frandom-seed=bazel-out/stub_armeabi-v7a-fastbuild/bin/_objs/hw/hw.pic.o' -fPIC -iquote . -iquote bazel-out/stub_armeabi-v7a-fastbuild/genfiles -iquote external/bazel_tools -iquote bazel-out/stub_armeabi-v7a-fastbuild/genfiles/external/bazel_tools -isystem external/bazel_tools/tools/cpp/gcc3 -c hw.cc -o bazel-out/stub_armeabi-v7a-fastbuild/bin/_objs/hw/hw.pic.o): com.google.devtools.build.lib.shell.BadExitStatusException: Process exited with status 1.
Target //:hw failed to build
INFO: Elapsed time: 0.231s, Critical Path: 0.01s

Hope this helps to clarify. I tried playing with the CROSSTOOL file but to no success.

Thanks

[hlopko]

Hi @fieldtest,

so you downloaded latest bazel, then updated cc_configure.bzl and CROSSTOOL.tpl to add armeabi-v7a toolchain, then compiled bazel, and you still see the error? You can see that the toolchain uses /bin/false instead of a compiler, so you want to fix that. Note that in order to use builtin auto-detection, you always have to recompile bazel. What you might find faster for debugging is to create your own CROSSTOOL or a repository similar to cc_configure.bzl.

We have some instructions here:
https://github.com/bazelbuild/bazel/wiki/Building-with-a-custom-toolchain

and there is a very similar issue being investigated over at:
#1353 (comment)

Let me know if you get stuck somewhere.
Cheers!

[madhutummi]

@mhlopko are u in slack Tensorflow group?

I need some help regarding TF Build, I am using bazel-0.3.2 from sources and getting following eror

"ERROR: tensorflow/core/BUILD:853:1: undeclared inclusion(s) in rule '//tensorflow/core:lib_internal':
this rule is missing dependency declarations for the following files included by 'tensorflow/core/lib/png/png_io.cc':
~/.cache/bazel/_bazel_madhu/a9aabe45cf3d94341ef4fb777deb58c5/external/zlib_archive/zlib.h'
~/.cache/bazel/_bazel_madhu/a9aabe45cf3d94341ef4fb777deb58c5/external/zlib_archive/zconf.h'."

[hlopko]

Nope, but feel free to ask the question on StackOverflow, both Bazel and Tensorflow teams monitor StackOverflow and answer questions there. And you'll help building user knowledge base.

[madhutummi]

@mhlopko did u get a chance to look into my issue?

[hlopko]

Nope, will eventually do once you post it to StackOverflow. But I would start by upgrading bazel, 0.3.2 is quite old.

[madhutummi]

Hi Yes with latest Bazel version I am getting the error as ERROR: /tensorflow/tensorflow.bzl:528:19: name 'DATA_CFG' is not defined.
When I stared debugging found it to be bazel issue, then I tried with older version then this error got fixed but above mentioned issues are occurring.

[madhutummi]

This issue got fixed.

[hlopko]

The static crosstool will be removed by #8546, so the confusion will be gone :)